The use of conventional gas turbines for the proposed industrial applications is well known. Thus, when a cycle comprising one or more gas turbines is placed upstream of an existing steam cycle of a power station, the overall energy efficiency of a conventional power station may go from 0.4 to 0.45 at the cost of extensive modification of the steam cycle, in particular by the addition of economizer exchangers. However, this technique proves to be expensive and only justifiable if the cost of the fuel itself is high. What is more, this technique involves an appreciable reduction in the useful power of the steam cycle. This results in only a modest overall gain in power, which for economic reasons is often unsatisfactory.
Another technique involves heat/force cycles, in which the gas turbine delivers mechanical energy and the exhaust gases deliver heat which can be exploited in various forms. In the case of a conventional gas turbine, this technique may prove to be useful when the necessary thermal energy is at low temperature, generally below 600.degree. C. On the other hand, this technique is not applicable when the thermal requirement is at a higher temperature level, in some cases even markedly higher, as is the case for instance in cement works, glassworks and steelworks or in certain furnaces. These plants, upstream of which the gas-turbine cycle may be applied, are all provided with heat regenerators for reheating the combustion air, this heat no longer being able to be recovered after the modification.
The conventional gas-turbine cycle involved in heat/force combined systems comprises an air compressor, a combustion chamber with a large excess of air and a turbine which generates the mechanical power. Downstream of the turbine, only the heat from the exhaust gases can be recovered.
Yet another technique involves combined cycles consisting of gas turbines and steam turbines of specific design. Their efficiency is currently between 0.5 and 0.53.
Even though conventional combined systems are operational, problems of implementation remain.
In so-called partial-oxidation systems, combustion is certainly complete, but staged. Firstly, partial oxidation is carried out, using air in substoichiometric quantity and steam, in a catalytic reactor which replaces the combustion chamber of the conventional gas-turbine cycle. Next, the combustion is completed downstream in the power turbine before the thermal energy of the exhaust gases is used.
The principles of a partial-oxidation gas turbine have already been presented earlier, but the arrival of nuclear power stations and other factors, such as the possibility of supplying with natural gas, have not encouraged its development. Moreover, it would also seem from the prior art that the technological elements essential for improving the application of these principles were not forthcoming.